Methods for processing silver halide color photographic materials (hereinafter referred to as color light-sensitive materials) generally comprise a color development step to form color images, a desilvering step to remove developed silver and undeveloped silver halide, and a water washing step and/or an image stabilizing step.
Heretofore, attempts have been made to reduce the processing time necessary for processing color light-sensitive materials. Recently, however, further reduction of the required processing time has been highly desirable in terms of reducing the total time period needed to finish processing, simplification of laboratory work, and miniaturization and simple operation of the processing system for small scale laboratories known as mini-labs, etc.
A method in which the time required to perform the color development step is reduced is known, and comprises processing a color light-sensitive material containing silver chloride or silver chlorobromide having a high silver chloride content. The color development speed of color light-sensitive materials containing silver chloride or silver chlorobromide having a high silver chloride content is extremely high as compared with, e.g., the color development speed of color light-sensitive materials containing silver chlorobromide having a high silver bromide contents, silver bromide, or silver iodobromide as employed in conventional color papers, etc. Therefore, the potential exists at present for reduction of developing time to a large extent.
Further, the color light-sensitive materials containing silver chloride or silver chlorobromide having a high silver chloride content is preferred since halogen ions released in a processing solution upon development are mainly or wholly chloride ions. On the contrary, halogen ions released are mainly or wholly bromide ions when color developing the other types of color light-sensitive materials referred to above. The chloride ions are characterized in that they have a remarkably small development inhibiting effect in comparison with bromide ions, and thus do not decrease the color development activity of the color developing solution even when accumulate therein in high concentrations. As a result, the amount of replenishing solution for the color developing solution can be reduced in the case of processing the color light-sensitive materials containing silver chloride or silver chlorobromide having a high silver chloride content using an automatic developing machine, as compared with color developing conventional color light-sensitive materials containing mainly silver bromide.
Hitherto, the desilvering step in the processing of color light-sensitive materials has been conducted by two different types of systems. One is a processing system wherein a bleaching step (by which developed silver is oxidized) and a fixing step (by which undeveloped silver halide and silver halide formed in the bleaching step are solubilized using a silver halide solvent) are carried out separately; the other is a processing system wherein the bleaching step and the fixing step are carried out at the same time in a single bath, that is, a so-called bleach-fixing system. Of these systems, the bleach-fixing system has the advantage of using only one processing solution, which is effective for purposes of miniaturization and simplification of the processing system, and thus, is practically employed in the processing of color light-sensitive materials such as color paper, color reversal paper, etc.
While various compounds have been proposed to be added to the bleach-fixing bath, a bleach-fixing solution containing a ferric complex salt of aminopolycarboxylic acid as a bleaching agent and a thiosulfate as a fixing agent is usually employed in practice, at present.
However, ferric complex salts of aminopolycarboxylic acids, such as a ferric complex salt of ethylenediaminetetraacetic acid, have a comparatively small oxidizing power and therefore, have insufficient bleaching power, although they are advantageous as to prevention of environmental pollution because of their low toxic character. As a result, color light-sensitive materials to which such a bleach-fixing system can be applied are limited to those having a low coating amount of silver.
With respect to methods for accelerating such a bleach-fixing step, a small number of techniques are known and only restricted number of accelerators have been investigated. For instance, compounds having a mercapto group or a disulfide group as described in U.S. Pat. No. 3,893,858, West German Pat. No. 1,290,812, etc., thiourea derivatives as described in U.S. Pat. No. 3,706,561, Japanese Patent Application (OPI) No. 32735/78, etc. (the term "OPI" as used herein means an "unexamined published application"), polyethyleneoxides as described in West German Pat. No. 2,748,430, etc., are exemplified. However, when these compounds having a mercapto group or a disulfide group, or the thiourea derivatives are employed as bleach-fixing accelerators for silver halide color photographic materials containing silver chloride or silver chlorobromide and having a low coating amount of silver, they tend to hinder the bleach-fixing reaction, and thus do not provide preferred results. Also, in the case of using polyethyleneoxides, sufficient effects are not obtained.
In British Pat. No. 990,846, a method in which an intermediate bath containing an iodide salt is provided between a color developing bath and a bleach-fixing bath in the overall processing sequence described. However, providing such an intermediate bath is not a preferred processing method in view of the recent trend aiming at simplification and miniaturization of the overall processing system. Further, a method of processing using a bleach-fixing solution containing an iodide salt is described in British Pat. No. 926,569. This method is effective in restrainig the hindrance of the bleach-fixing reaction during bleach-fixing processing of color light-sensitive material containing silver chlorobromide wide a low coating amount of silver and hydrophilic and diffusion-resistant couplers. However, addition of the iodide salt to the bleach-fixing solution rather adversely affects on the bleach-fixing reaction of color light-sensitive materials containing silver chlorobromide having a high silver bromide content and oil-protected type couplers which are generally used in practice at present, and preferred results can not be obtained.
Moreover, in Japanese Patent Publication No. 11854/78 and Japanese Patent Application (OPI) No. 87036/76, a method of processing color light-sensitive materials containing silver chlorobromide or silver iodobromide having a high silver bromide content in the presence of a halide salt or ammonium bromide is described. However, in this method, a small amount of silver or silver salt can not be removed and remains in the photographic materials, particularly when color light-sensitive materials containing silver chlorobromide having a high silver chloride content with a low coating amount of silver (such as color paper) are subjected to bleach-fixing processing. Such a small amount of remaining silver is particularly present at image portions having high density, and deteriorates color reproduction of the color images. This tendency is especially remarkable in yellow and red images.
The amount of remaining silver in high density portions is larger when color light-sensitive materials containing silver chloride or silver chlorobromide having a high silver chloride content as described above are subjected to bleach-fixing processing after color development processing in comparison with the case wherein conventional color light-sensitive materials containing silver chlorobromide having a high silver bromide content are processed in the same manner as above.